Out of $C_{6}H_{5}CH_{2}Cl$ and $C_{6}H_{5}CHClC_{6}H_{5},$ which is more easily hydrolysed by aqueous $KOH$?

(C_{6}H_{5}CHCLC_{6}H_{5}) The hydrolysis of alkyl halides by aqueous $KOH$ often proceeds via an $S_{N}1$ mechanism,which involves the formation of a carbocation intermediate.
The stability of the carbocation determines the ease of hydrolysis. $A$ more stable carbocation is formed more readily,leading to faster hydrolysis.
$1$. $C_{6}H_{5}CH_{2}Cl$ ionizes to form a benzyl carbocation $(C_{6}H_{5}CH_{2}^{+})$,which is stabilized by resonance with one phenyl ring.
$2$. $C_{6}H_{5}CHClC_{6}H_{5}$ ionizes to form a diphenylmethyl carbocation $(C_{6}H_{5}CH^{+}C_{6}H_{5})$,which is stabilized by resonance with two phenyl rings.
Since the diphenylmethyl carbocation is more stable due to extended resonance with two phenyl rings compared to the benzyl carbocation,$C_{6}H_{5}CHClC_{6}H_{5}$ undergoes hydrolysis more easily than $C_{6}H_{5}CH_{2}Cl$.